The INB, a Division of the UPR Medical Sciences Campus (MSC), is located in Old San Juan, about seven miles from the main campus. The RCMI Program at UPR-MSC has supported research activities at the INB since 1991. Many of these activities continue to utilize the Institute's animal facilities (AFs), which constitutes a satellite unit of the Animal Resources Center (ARC) of UPR-MSC. As the research activities have increased and expanded in scope, the mammalian facility has become extremely limited, restricting the number of species and total number of animals that can be used for research by the present faculty. The present capacity is insufficient to meet the needs of the scientific community at the Institute, thus impeding their productivity, jeopardizing continued funding of present projects and limiting opportunity to develop new projects. In addition, there is no procedure room, only limited space for storage of food and cages, and no wash room facility for the staff. Although the present heating, ventilation, and air-conditioning (HVAC) system is functional; it does not allow for climate control of individual cubicles. The AF also lacks an adequate cage washing facility, and there is serious concern that the present situation may endanger AAALAC accreditation of the facility. The overall goal of the present application is to improve and expand the existing housing facilities for mammals. To achieve this goal, it is proposed to renovate approximately 2,700 sq. ft. of underutilized space adjacent to the existing AF. This will create new animal holding and support spaces. The following units will be added after remodeling: 1) twelve animal holding cubicles organized in three pods; 2) a shared procedure room; 3) storage space; 4) locker, toilet and shower room for the staff; 5) electrical and plumbing connections; 6) exit corridors to comply with life safety code, 7) a new HVAC system to serve the existing and proposed areas, and 8) a new mechanical room. Renovations will also include reconfiguring the existing animal holding area to include a cage washing facility, and purchasing the equipment necessary for the operation of the proposed animal holding facility, i.e., cage washer, autoclave, and procedure room equipment. The requested funds for renovation of the mammalian facility will allow the correction of deficiencies and future growth of the research program of the IN. As one of the RCMI activities, the facility will further the main goal of the Program at UPR-MSC; namely, the development of a strong research infrastructure at UPR-MSC.